How to choose network protocol for real-time streaming

  • Posted by elecard
  • March 3, 2021 10:33 AM GMT
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The choice of a network protocol for real-time streaming depends on many factors such as number of end-users, type of their receiving devices, desired latency, and network type. We will consider some typical tasks and possible solutions.

Task 1: Organize streaming for a great number of users with stationary devices such as STB and TV sets.

Solution. The prepared content is delivered to a CAS point for signal encryption and modulation to DVB C/T/T2/S. Content is delivered within the operator's local network where data loss is unlikely. For that task, best-effort protocols such as UDP and RTP are used. They provide a minimum delay of around 80 ms and do not consume additional traffic.

Best-effort protocols are well suited for content delivery within local networks, for example, hotels and operator networks.

Task 2: Organize broadcasting for a great number of mobile devices and SmartTVs.

Solution. For that task, the adaptive streaming is used. The content is prepared in several profiles, so users with any Internet speed can get the corresponding video quality. Each profile has its own characteristics.

For adaptive streaming, OTT protocols such as Apple HLS and MPEG-DASH are used. These protocols make an HTTP connection that guarantees data delivery. Content is packetized in equal segments that are delivered to CDN. CDN distributes content to users and reduces the load on head-end by means of cashing.

The delay can reach from several to dozens seconds depending on specified segment length and other factors.

Protocols providing guaranteed delivery and adaptive streaming are ideal in case of a large number of users and unstable Internet connection.

Task 3: Organize broadcasting of several channels via the Internet with minimal delay.

Solution. Prepared content is sent via the Internet using protocols with guaranteed delivery. SRT is the best option for this task. It operates on the basis of UDT (UDP-based Data Transfer Protocol) and ARQ packet recovery technology. Compared to OTT protocols, SRT has a lower delay ranging from 120 ms.

Read our article to learn more about low latency protocols.

The Elecard CodecWorks encoder supports all the above-listed protocols and allows solving all the tasks mentioned. You can select a network protocol on the Output tab during the creation of the encoding schema.

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